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authorFilip Bozuta <Filip.Bozuta@syrmia.com>2020-08-11 18:45:51 +0200
committerLaurent Vivier <laurent@vivier.eu>2020-08-27 12:29:50 +0200
commit02e5d7d78e423bf8b3ebb66ab36bdaa7e962312a (patch)
treed270a04552cc96657d5e04a01e160f21e6d7cc7f /linux-user/i386
parent7c89f343836049b4732acde00db401e633335f8c (diff)
linux-user: Add strace support for printing arguments of syscalls used to lock and unlock memory
This patch implements strace argument printing functionality for following syscalls: * mlock, munlock, mlockall, munlockall - lock and unlock memory int mlock(const void *addr, size_t len) int munlock(const void *addr, size_t len) int mlockall(int flags) int munlockall(void) man page: https://man7.org/linux/man-pages/man2/mlock.2.html Implementation notes: Syscall mlockall() takes an argument that is composed of predefined values which represent flags that determine the type of locking operation that is to be performed. For that reason, a printing function "print_mlockall" was stated in file "strace.list". This printing function uses an already existing function "print_flags()" to print the "flags" argument. These flags are stated inside an array "mlockall_flags" that contains values of type "struct flags". These values are instantiated using an existing macro "FLAG_TARGET()" that crates aproppriate target flag values based on those defined in files '/target_syscall.h'. These target flag values were changed from "TARGET_MLOCKALL_MCL*" to "TARGET_MCL_*" so that they can be aproppriately set and recognised in "strace.c" with "FLAG_TARGET()". Value for "MCL_ONFAULT" was added in this patch. This value was also added in "syscall.c" in function "target_to_host_mlockall_arg()". Because this flag value was added in kernel version 4.4, it is enwrapped in an #ifdef directive (both in "syscall.c" and in "strace.c") as to support older kernel versions. The other syscalls have only primitive argument types, so the rest of the implementation was handled by stating an appropriate printing format in file "strace.list". Syscall mlock2() is not implemented in "syscall.c" and thus it's argument printing is not implemented in this patch. Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20200811164553.27713-4-Filip.Bozuta@syrmia.com> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Diffstat (limited to 'linux-user/i386')
-rw-r--r--linux-user/i386/target_syscall.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/linux-user/i386/target_syscall.h b/linux-user/i386/target_syscall.h
index 2854758134..ed356b3908 100644
--- a/linux-user/i386/target_syscall.h
+++ b/linux-user/i386/target_syscall.h
@@ -151,8 +151,9 @@ struct target_vm86plus_struct {
#define TARGET_CLONE_BACKWARDS
#define TARGET_MINSIGSTKSZ 2048
-#define TARGET_MLOCKALL_MCL_CURRENT 1
-#define TARGET_MLOCKALL_MCL_FUTURE 2
+#define TARGET_MCL_CURRENT 1
+#define TARGET_MCL_FUTURE 2
+#define TARGET_MCL_ONFAULT 4
#define TARGET_WANT_OLD_SYS_SELECT
#endif /* I386_TARGET_SYSCALL_H */